1. Technical Field
The present invention relates to an image forming apparatus such as a printer, a facsimile machine, or a copier.
2. Related Art
Conventionally, a so-called tandem type image forming apparatus has been known, in which a plurality of latent image carriers are disposed along a surface moving direction of an intermediate transfer member or a recording medium conveyance member. The tandem-type image forming apparatus further includes, around each latent image carrier, a charger to uniformly charge a surface of the latent image carrier, a recording head to expose the surface of the latent image carrier to form a latent image, and a developing device to develop the latent image formed on the latent image carrier.
JP-4781753-B and JP-2010-271743-A disclose an image forming apparatus including an upper cover rotatably disposed on the apparatus housing as a holder to hold a plurality of recording heads. The upper cover is so disposed as to rotate about an end of the housing and parallel to the plurality of latent image carriers. When the upper cover is closed, the plurality of recording heads is positioned at a latent image forming position where the latent image is formed on the surface of the latent image carrier. If the upper cover is opened, the plurality of recording heads moves from the latent image forming position to a retracted position.
When the recording head moves to the retracted position, an image forming unit including the latent image carrier, the charger, and the developing device can be pulled out vertically, so that the image forming unit can be pulled out from an upper opening of the housing.
FIG. 16 is a schematic view of an example of an image forming apparatus and represents a state in which an upper cover 50 is opened and image forming units are taken out.
In the image forming apparatus as background art as illustrated in FIG. 16, an inner cover 40 to hold each of the recording heads 70Y, 70M, 70C, and 70K and the upper cover 50 are so disposed as to rotate about a shaft 50. Each recording head 70Y, 70M, 70C, or 70K is rotatable with respect to the inner cover 40 via a pair of arm members 76Y, 76M, 76C, and 76K. One of the pair of arm members retains one longitudinal end of the recording head and the other retains the other longitudinal end of the recording head.
Further, the inner cover 40 includes toner cartridges, not shown, containing toner to be supplied. When the upper cover 50 and the inner cover 40 are rotated counterclockwise in FIG. 16, image forming units 1Y, 1M, 1C, and 1K disposed inside the housing 90 are exposed and can be taken out from the upper part.
Side plates are disposed at both lateral ends of the recording head in the longitudinal direction, that is, a main scanning direction. One side plate is opposed to one longitudinal end of the recording head and the other side plate is opposed to the other longitudinal end of the recording head. Guide members 91Y, 91M, 91C, and 91K each extend from a latent image position of the recording head toward an opening of the housing.
When the inner cover 40 is being closed, each recording head moves along an arc-shaped moving locus about a rotary supporting point of the inner cover 40. Each recording head 70Y, 70M, 70C, or 70K includes a projection 72Y, 72M, 72C, or 72K, respectively, each as a guided portion disposed at each arm member. In associated movement of closing the inner cover 40, each recording head 70Y, 70M, 70C, or 70K enters into the housing and the projection 72Y, 72M, 72C, or 72K contacts each guide member 91Y, 91M, 91C, or 91K. When the inner cover 40 is further closed, the guide member regulates the arc-shaped moving of each recording head with its center at the rotary supporting point of the inner cover 40. Accordingly, when the recording head moves along the arc-shaped moving locus in the housing, each recording head moves downward while moving leftward (toward the shaft 51). When the guided portion abuts the guide member, moving toward the left is regulated. Because each recording head is disposed swingably relative to the inner cover, if the moving toward left is regulated by the guide member, the recording head moves counterclockwise relative to the inner cover 40, so that each recording head moves downward to the latent image forming position guided by the guide member.
The image forming apparatus includes a first guide member disposed at one end or a first end to guide one end of the recording head to the latent image forming section; and a second guide member disposed at the other end or a second end to guide the other end of the recording head to the latent image forming position. Each guide member extends from the latent image forming position to the position close to the opening of the housing. Accordingly, a space for a drive transmission device such as a gear to transmit driving force of a motor to the toner bottle cannot be obtained around a side wall opposite the second end of the recording head in the housing. Provision of such a device in the subject area may lead to a large-sized apparatus.